Community science data highlight the vast colour pattern variations in the Japanese natricine snake (Rhabdophis tigrinus)

Abstract Colour pattern variations in animals range from a small number of discrete morphs to continuous variations. However, the possibility that the degree itself is shaped by bias produced by limited observations cannot be excluded. Through a community science approach, also known as citizen science, we refined the definitions of the colour pattern morphs of the Japanese natricine snake, Rhabdophis tigrinus. Despite the limited number of geographical observations, R. tigrinus has been classified into six distinct colour pattern morphs over the past decades: three region-specific morphs, two hypopigmented morphs, and one hyperpigmented morph. However, our newly collected community science images of R. tigrinus revealed that 123 colour pattern combinations of R. tigrinus have emerged across the Japanese Archipelago. The community science images with detailed geographical information also provided insights into the anti-predatory functions of R. tigrinus colour patterns through an association between blotch size and habitat temperature via the flicker-fusion effect. Our results highlight the advantages of using community science data in overcoming observational biases and investigating intraspecific colour pattern variations across a wide geographical range.